1. Field of the Invention
This invention relates to an electrode for a projection welding machine, of the type having a parts receiving hole, said electrode being characterized in that a magnet is placed in said receiving hole.
2. Description of the Prior Art
As for electrodes of this type, mention may be made of "Welding Electrode for Bar-Like Parts" (applied for patent on Jul. 9, 1963 (2. complete)) and "Method of Introducing Bar-Like Parts" (applied for patent on April 1 (3)), which I invented. The former includes a magnet installed in the innermost region of the guide hole of the electrode to assist a bar-like part in advancing into the guide hole. The latter includes a magnet adapted to be vertically moved in the electrode, and a guide pin disposed between a bar-like part and the magnet, the magnetic force being transmitted to a bar-like part through the guide pin.
In the former mentioned in the paragraph of Prior Art, although the magnet is disposed in the innermost region of the guide hole, the lack of a construction for dissipating the heat transferred to the magnet presents a problem that the magnetic force decreases when the magnet is overheated. On the other hand, in the latter, although the presence of the guide pin limits the transfer of heat to the magnet, it presents a problem similar to the one in the former in the dissipation of heat from the magnet.